Surgical knife



FIG. 1 is a perspective view of the surgical knife;

FIG. 2 is a front view thereof;

FIG. 3 is a back view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a bottom view thereof; and,

FIG. 7 is a top view thereof.

The broken lines showing on the sides and bottom portion of the surgical knife are for the purpose of illustrating environmental structure and form no part of the claimed design. 

CLAIM The ornamental design for a surgical knife, as shown and described. 